As is known in the optical arts, distributed fiber sensing (DFS) systems, methods, and structures—including distributed vibration sensing (DVS), distributed acoustic sensing (DTS), and Brillouin optical time domain reflectometry (BOTDR), changes in optical fiber may be detected and located by using optical pulse interrogation methods. In such operations, a single optical fiber is dedicated for use by a single sensing system, or switched between systems at different times if continuous, real-time updates are not required.
Presently, there is growing demand for in-service, commercial optical communications systems to perform optical fiber sensing. However, as communications channels require continuous operation—it remains quite difficult to integrate communications system(s) and sensing system(s) on a common (the same) optical fiber. One reason for such difficulty is that the instantaneous operating power of optical pulse reflectometry in fiber sensing systems is necessarily much higher as compared to communications channels, thus degrading communication performance as a result of any fiber nonlinearity. As a result, the art has employed separate optical fibers—which may be included in a common fiber bundle—for optical communications and optical sensing thereby avoiding interference problems altogether.
Accordingly, a continuing need exists in the art for systems, methods, and structures that provide simultaneous optical communications and optical sensing on a common optical fiber.